I believe your information to be false. I have worked on Canadian vehicles that are brought into the US with the same speedometer/odometer assemblies as they left the factory with, including vehicles as new as an ML. As long as the odometer is marked "KM" I believe you are fine, and the speedometer has to read both KMH and MPH, as I'm sure the vehicle in question (a Canadian model) already has. Makes no difference if KMH or MPH is the "primary" or larger marking, as long as both are present.

Gilly